Question

The first term of a $G.P.$ whose second term is $2$ and sum to infinity is $8$ will be

• A. $6$
• B. $3$
• C. $4$
• D. $1$

Answer 1

Answer: (C)

$4$

$ar=2,\frac{a}{1-r}=\frac{1}{8}$. Eliminate $r$ and we get
$a^2-8a+16=0\therefore (a-4{)}^2=0$ or $a=4$